JP6837550B2 - Photo-aligned copolymer, photo-aligned film, optical laminate and image display device - Google Patents

Description

The present invention relates to photoalignable copolymers, photoalignment films, optical laminates and image display devices.

Optical films such as optical compensation sheets and retardation films are used in various image display devices from the viewpoints of eliminating image coloring and expanding the viewing angle.
A stretched birefringent film has been used as the optical film, but in recent years, it has been proposed to use an optically anisotropic layer using a liquid crystal compound instead of the stretched birefringent film.

It is known that such an optically anisotropic layer is provided with an alignment film on a support forming the optically anisotropic layer in order to orient the liquid crystal compound, and rubbing is provided as the alignment film. A photo-alignment film that has undergone photo-alignment treatment instead of treatment is known.

For example, Patent Document 1 discloses an embodiment in which a polymer layer containing a compound containing a repeating unit having 2 to 3 photo-oriented groups is used as an orientation layer ([Claim 1] [Claim 7]]. [Claim 8]).

Further, Patent Document 2 discloses a liquid crystal alignment layer formed from a thermosetting film-forming composition containing an acrylic copolymer having a photodimerization site such as a cinnamoyl group and a cross-linking agent ([Claim]. 1] [Claim 3] [Claim 11] <0028>).

Special Table 2003-505561 International Publication No. 2010/150748

The present inventors have examined polymers having photo-oriented groups described in Patent Documents 1 and 2, and found that, depending on the type of monomer, a photo-aligned film formed by using the obtained polymer or copolymer. It was clarified that the orientation with respect to the liquid crystal compound (hereinafter, also abbreviated as "liquid crystal orientation") may be inferior.

Therefore, the present invention provides a photo-alignment copolymer capable of producing a photo-alignment film having excellent liquid crystal orientation, and a photo-alignment film, an optical laminate, and an image display device produced by using the photo-alignment copolymer. That is the issue.

As a result of diligent studies to achieve the above problems, the present inventors have prepared by using a copolymer having a repeating unit containing two or more specific photo-oriented groups and a repeating unit containing a crosslinkable group. We have found that the liquid crystal orientation of the photoalignment film is good, and completed the present invention.
That is, the present inventors have found that the above-mentioned problems can be achieved by the following configurations.

[1] A photo-oriented copolymer having a repeating unit A represented by the formula (1) containing a photo-oriented group and a repeating unit B represented by the formula (2) containing a crosslinkable group.

^{[2] L 1} in the formula (1) ^{and L 2} in the formula (2) are independently linear, branched or cyclic alkylene groups having 1 to 10 carbon atoms, and have 6 to 12 carbon atoms. The photo-oriented copolymer according to [1], which is a divalent linking group in which at least two or more groups selected from the group consisting of an arylene group, an ether group, a carbonyl group, and an imino group are combined.

[3] The photo-oriented copolymer according to [1] or [2], wherein A in the formula (1) is a trivalent to hexavalent linking group.
[4] A in the formula (1) is an m-valent hydrocarbon group having 1 to 24 carbon atoms which may have a substituent, and a part of the carbon atoms constituting the hydrocarbon group is hetero. The photo-orientation copolymer according to [1] or [2], which is a hydrocarbon group which may be substituted with an atom.
[5] The photooriented copolymer according to any one of [1] to [4], wherein A in the formula (1) is a linking group containing an alicyclic hydrocarbon group.

[6] The photoorientation according to any one of [1] to [5], wherein X in the formula (2) is a crosslinkable group represented by any of the formulas (3) to (5) described later. Sex copolymer.
[7] The photo-oriented copolymer according to [6], wherein X in the formula (2) is a crosslinkable group represented by the formula (3) or (4).

^{[8] R 2} , R ³ , R ⁴ , R ⁵ and R ⁶ in the formula (1) are independently hydrogen atoms or halogen atoms, linear, branched or branched with 1 to 20 carbon atoms. Cyclic alkyl group, linear alkyl halide group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, aryl group having 6 to 20 carbon atoms, aryloxy group having 6 to 20 carbon atoms, cyano group. , An amino group, and a photoorientable copolymer according to any one of [1] to [7], which is a substituent selected from the group consisting of a group represented by the formula (7) described later.
[9] The photoorientation according to any one of [1] to [8], wherein at least R ^{4 represents a substituent among R 2} , R ³ , R ⁴ , R ⁵ and R ^{6 in} the formula (1). Sex copolymer.
[10] The photo-oriented copolymer according to any one of [1] to [9], wherein ^{R 4} in the formula (1) is an electron-donating substituent.

[11] The photooriented copolymer according to any one of [1] to [10], wherein the content mass X of the repeating unit A and the content mass Y of the repeating unit B satisfy the following formula (8).
0.4 ≤ X / (X + Y) ≤ 0.8 ... (8)
[12] The photooriented copolymer according to [11], wherein the content mass X of the repeating unit A and the content mass Y of the repeating unit B satisfy the following formula (9).
0.45 ≤ X / (X + Y) ≤ 0.65 ... (9)

[13] A photo-aligned film formed by using the composition for a photo-aligned film containing the photo-aligned copolymer according to any one of [1] to [12].
[14] An optical laminate having the photoalignment film according to [13] and an optically anisotropic layer formed by using a liquid crystal composition containing a liquid crystal compound.
[15] An image display device having the optical laminate according to [14].

According to the present invention, a photo-alignment copolymer capable of producing a photo-alignment film having excellent liquid crystal orientation, and a photo-alignment film, an optical laminate, and an image display device produced by using the photo-alignment copolymer are provided. be able to.

Hereinafter, the present invention will be described in detail.
The description of the constituent elements described below may be based on typical embodiments of the present invention, but the present invention is not limited to such embodiments.
In the present specification, the numerical range represented by using "~" means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.

[Photo-oriented copolymer]
The photo-oriented copolymer of the present invention has a repeating unit A represented by the formula (1) containing a photo-oriented group and a repeating unit B represented by the formula (2) containing a crosslinkable group. It is a photo-oriented copolymer.

In the above formula (1), R ¹ represents a hydrogen atom or a methyl group, L ¹ represents a single bond or a divalent linking group, A represents an m-valent linking group, and R ² and R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom or substituent. Of R ² , R ³ , R ⁴ , R ⁵ and R ⁶ , two adjacent groups may be bonded to form a ring. m represents an integer of 3 or more, and n represents an integer of m-1. The plurality of R ² , R ³ , R ⁴ , R ⁵ and R ⁶ may be the same or different, respectively.
In the above formula (2), R ⁷ represents a hydrogen atom or a methyl group, L ² represents a divalent linking group, and X represents a crosslinkable group.

A photo-aligned film produced using a copolymer having a repeating unit A represented by the formula (1) containing a photo-oriented group and a repeating unit B represented by the formula (2) containing a crosslinkable group Since the cinnamoyl group is a photo-oriented group that produces a liquid crystal orientation ability by absorbing light, the liquid crystal orientation is good.
This is not clear in detail, but the present inventors speculate as follows.
That is, since the repeating unit A contains a plurality of photo-oriented groups, the concentration of the photo-oriented groups per unit area increases after the photo-aligned film is formed, so that the site interacts with the liquid crystal compound. In addition, it is considered that the fixation of the orientation was promoted by the inclusion of the crosslinkable group in the repeating unit B, and as a result, the liquid crystal orientation of the formed photoalignment film was improved.

The divalent linking group represented ^{by L 1} in the above formula (1) ^{and L 2} in the above formula (2) will be described.

As the divalent linking group, a linear chain having 1 to 10 carbon atoms is used because the photo-aligning group easily interacts with the liquid crystal compound and the liquid crystal orientation of the produced photo-alignment film becomes better. Consists of a linear, branched or cyclic alkylene group, an arylene group having 6 to 12 carbon atoms, an ether group (-O-), a carbonyl group (-C (= O)-), and an imino group (-NH-). It is preferably a divalent linking group in which at least two or more groups selected from the group are combined.

Regarding the linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, the linear alkylene group specifically includes, for example, a methylene group, an ethylene group, a propylene group, a butylene group and a pentylene group. , Hexylene group, decylene group and the like.
Specific examples of the branched alkylene group include a dimethylmethylene group, a methylethylene group, a 2,2-dimethylpropylene group and a 2-ethyl-2-methylpropylene group.
Specific examples of the cyclic alkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, a cyclooctylene group, a cyclodecylene group, an adamantane-diyl group, and a norbornane-diyl group. , Exo-tetrahydrodicyclopentadiene-diyl group and the like, and among them, the cyclohexylene group is preferable.

Specific examples of the arylene group having 6 to 12 carbon atoms include a phenylene group, a xylylene group, a biphenylene group, a naphthylene group, a 2,2'-methylenebisphenyl group and the like, and a phenylene group is preferable. ..

Of these divalent linking groups, an ester bond (-C (= O) O-) in which a carbonyl group and an ether group are combined, and a linking group in which a phenylene group and an ether group are combined are more preferable. It is more preferably −C (= O) O−.

Next, the m-valent linking group represented by A in the following formula (1) will be described.

In the present invention, m represents an integer of 3 or more, preferably an integer of 3 to 6, more preferably an integer of 3 to 5, and even more preferably 3 or 4.

In the present invention, A in the above formula (1) is a substituent because the photo-oriented group easily interacts with the liquid crystal compound and the liquid crystal orientation of the produced photo-aligned film becomes better. It is an m-valent hydrocarbon group having 1 to 24 carbon atoms which may have a hydrocarbon group, and a part of carbon atoms constituting the hydrocarbon group may be substituted with a heteroatom (hereinafter referred to as a hydrocarbon group). It is abbreviated as "m-valent hydrocarbon group A").

Specific examples of the m-valent hydrocarbon group A include groups represented by the following formulas (a1) to (a4). In the following formulas (a1) ~ (a4), ^{* L} represents a bonding position with ^{L 1} in the formula (1), an oxygen atom previous * is a carbonyl group in the formula (1) Represents the bond position with the constituent carbon atoms.

Examples of the substituent which the m-valent hydrocarbon group A may have include an alkylene group, an arylene group and an imino group include an alkyl group, an alkoxy group and a halogen atom. Examples include hydroxyl groups.
As the alkyl group, for example, a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms is preferable, and an alkyl group having 1 to 8 carbon atoms (for example, a methyl group, an ethyl group, a propyl group or an isopropyl group) is preferable. Group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, cyclohexyl group, etc.) are more preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable, and a methyl group or an ethyl group is used. Is particularly preferable.
As the alkoxy group, for example, an alkoxy group having 1 to 18 carbon atoms is preferable, and an alkoxy group having 1 to 8 carbon atoms (for example, a methoxy group, an ethoxy group, an n-butoxy group, a methoxyethoxy group, etc.) is more preferable, and carbon. It is more preferably an alkoxy group of numbers 1 to 4, and particularly preferably a methoxy group or an ethoxy group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and among them, a fluorine atom and a chlorine atom are preferable.

In the present invention, the m-valent hydrocarbon group A is of the alicyclic type because the photo-oriented group easily interacts with the liquid crystal compound and the liquid crystal orientation of the produced photo-aligned film becomes better. It is preferably a linking group containing a hydrocarbon group, and more preferably a group represented by the above formula (a2).

Next, the hydrogen atom or substituent represented ^{by R 2} , R ³ , R ⁴ , R ⁵ and R ⁶ in the following formula (1) will be described.

^{As R 2} , R ³ , R ⁴ , R ⁵ and R ^{6 in the} above formula (1), the photo-aligning group easily interacts with the liquid crystal compound, and the liquid crystal orientation of the produced photo-alignment film is improved. For better reasons, each independently hydrogen atom; or; halogen atom, linear, branched or cyclic alkyl group with 1 to 20 carbon atoms, linear halogenation with 1 to 20 carbon atoms. From an alkyl group, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a cyano group, an amino group, and a group represented by the following formula (7). Substituents selected from the group;

In the above formula (7), * represents the bond position with the benzene ring in the formula (1), and R ⁹ represents a monovalent organic group.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and among them, a fluorine atom and a chlorine atom are preferable.

Regarding the linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, the linear alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, and specifically, for example, a methyl group. Ethyl group, n-propyl group and the like can be mentioned.
The branched alkyl group is preferably an alkyl group having 3 to 6 carbon atoms, and specific examples thereof include an isopropyl group and a tert-butyl group.
The cyclic alkyl group is preferably an alkyl group having 3 to 6 carbon atoms, and specific examples thereof include a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group.

As the linear alkyl halide group having 1 to 20 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms is preferable, and specifically, for example, a trifluoromethyl group, a perfluoroethyl group, or a perfluoropropyl group. , Perfluorobutyl group and the like, and among them, a trifluoromethyl group is preferable.

The alkoxy group having 1 to 20 carbon atoms is preferably an alkoxy group having 1 to 8 carbon atoms, and specific examples thereof include a methoxy group, an ethoxy group, an n-butoxy group and a methoxyethoxy group. A methoxy group or an ethoxy group is preferable.

The aryl group having 6 to 20 carbon atoms is preferably an aryl group having 6 to 12 carbon atoms, and specific examples thereof include a phenyl group, an α-methylphenyl group, a naphthyl group, and the like. Among them, the phenyl group is used. preferable.

The aryloxy group having 6 to 20 carbon atoms is preferably an aryloxy group having 6 to 12 carbon atoms, and specific examples thereof include a phenyloxy group and a 2-naphthyloxy group. Among them, a phenyloxy group. Is preferable.

Examples of the amino group include a primary amino group (-NH ₂ ); a secondary amino group such as a methylamino group; a dimethylamino group, a diethylamino group, a dibenzylamino group, and a nitrogen-containing heterocyclic compound (for example, pyrrolidine). , Piperidine, piperazine, etc.), such as a tertiary amino group having a nitrogen atom as a bond.

Regarding the group represented by the above formula (7) ^{, examples of the monovalent organic group represented by R 9} in the above formula (7) include linear or cyclic alkyl groups having 1 to 20 carbon atoms. Be done.
The linear alkyl group is preferably an alkyl group having 1 to 6 carbon atoms, and specific examples thereof include a methyl group, an ethyl group and an n-propyl group, and among them, a methyl group or an ethyl group is used. preferable.
As the cyclic alkyl group, an alkyl group having 3 to 6 carbon atoms is preferable, and specific examples thereof include a cyclopropyl group, a cyclopentyl group, a cyclohexyl group and the like, and among them, a cyclohexyl group is preferable.
^{The monovalent organic group represented by R 9} in the above formula (7) may be a combination of a plurality of the above-mentioned linear alkyl group and cyclic alkyl group directly or via a single bond. Good.

^{In the present invention, R 2} and R ^{3 in the} above formula (1) are for the reason that the photo-aligning group easily interacts with the liquid crystal compound and the liquid crystal orientation of the produced photo-alignment film becomes better. , R ⁴ , R ⁵ and R ⁶ preferably, at least R ⁴ represents the above-mentioned substituent, and further, the rigidity of the obtained photo-orientation copolymer is improved, and the photo-orientation produced is produced. It is more preferable that ^{R 2} , R ³ , R ⁵ and R ⁶ all represent hydrogen atoms for the reason that the heat resistance of the film is further improved.

In the present invention, the reason the reaction efficiency upon light irradiation to obtain the optical alignment film is improved, it is preferable R ⁴ in the formula (1) is an electron donating substituent.
Here, the electron-donating substituent (electron-donating group) means a substituent having a Hammett value (Hammett substituent constant σp) of 0 or less, and for example, among the above-mentioned substituents, an alkyl group, Examples thereof include an alkyl halide group and an alkoxy group. Among them, a cyclic alkyl group (for example, a cyclohexyl group) and an alkoxy group (for example, a methoxy group) are used because the liquid crystal orientation of the produced photoalignment film is improved. ) Is preferable.

Specific examples of the repeating unit A represented by the formula (1) containing a photo-oriented group include the repeating units A-1 to A-76 shown below. In the following formulas, Me represents a methyl group, Et represents an ethyl group, ⁱ Pr denotes an isopropyl group.

Next, with respect to the repeating unit B represented by the formula (2) containing a crosslinkable group, the crosslinkable group represented by X in the following formula (2) will be described.

In the present invention, the crosslinkable group is preferably a so-called self-crosslinkable group in which cross-linking proceeds between functional groups without adding a cross-linking agent. Specifically, the following formulas (3) to (5) are specified. ) Is more preferable, and the crosslinkable group represented by the following formula (3) or (4) is further preferable. In the following formulas (3) to (5), * represents the bond position with ^{L 2 in the above formula (2), and R 8} represents any of a hydrogen atom, a methyl group and an ethyl group.

Specific examples of the repeating unit B represented by the formula (2) containing a photo-oriented group include the repeating units B-1 to B-3 shown below.

The photo-oriented copolymer of the present invention has the above-mentioned content mass X of the repeating unit A for the reason that the rigidity of the obtained photo-oriented copolymer is improved and the heat resistance of the produced photo-aligned film is improved. It is preferable that the content mass Y of the repeating unit B described above satisfies the following formula (8), and the photo-oriented group easily interacts with the liquid crystal compound to produce a photo-aligned film. It is more preferable that the following formula (9) is satisfied for the reason that the liquid crystal orientation of the above is better.
0.4 ≤ X / (X + Y) ≤ 0.8 ... (8)
0.45 ≤ X / (X + Y) ≤ 0.65 ... (9)

The photo-oriented copolymer of the present invention may have other repeating units in addition to the above-mentioned repeating unit A and repeating unit B as long as the effects of the present invention are not impaired.
Examples of the monomer (radical polymerizable monomer) forming such another repeating unit include an acrylic acid ester compound, a methacrylic acid ester compound, a maleimide compound, an acrylamide compound, an acrylonitrile, a maleic anhydride, and a styrene compound. Examples include vinyl compounds.

The method for synthesizing the photoorientable copolymer of the present invention is not particularly limited, and for example, the monomer forming the repeating unit A described above, the monomer forming the repeating unit B described above, and any other repeating unit are formed. It can be synthesized by mixing the monomers to be used and polymerizing them in an organic solvent using a radical polymerization initiator.

The weight average molecular weight (Mw) of the photo-aligned copolymer of the present invention is 1000 to 1000 because the rigidity of the obtained photo-aligned copolymer is improved and the heat resistance of the produced photo-aligned film is improved. 500,000 is preferable, and 30,000 to 200,000 is more preferable because the orientation becomes better.
Here, the weight average molecular weight and the number average molecular weight in the present invention are values measured by the gel permeation chromatography (GPC) method under the conditions shown below.
-Solvent (eluent): THF (tetrahydrofuran)
-Device name: TOSOH HLC-8320GPC
-Column: Use by connecting three TOSOH TSKgel Super HZM-H (4.6 mm x 15 cm) -Column temperature: 40 ° C
-Sample concentration: 0.1% by mass
-Flow velocity: 1.0 ml / min
-Calibration curve: TOSOH TSK standard polystyrene Mw = 2800000-1050 (Mw / Mn = 1.03 to 1.06) 7 samples calibration curve is used.

[Photo-alignment film]
The photo-alignment film of the present invention is a composition for a photo-alignment film containing the above-mentioned photo-orientation copolymer of the present invention (hereinafter, formally referred to as "composition for a photo-alignment film of the present invention"). It is a photo-alignment film formed by using.
The film thickness of the photoalignment film is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 to 1000 nm, more preferably 10 to 700 nm.

The content of the photo-oriented copolymer of the present invention in the composition for a photo-aligned film of the present invention is not particularly limited, but when an organic solvent described later is contained, 0.1 to 50 parts by mass of the organic solvent is used. It is preferably parts by mass, more preferably 0.5 to 10 parts by mass.

The composition for a photoalignment film of the present invention preferably contains an organic solvent from the viewpoint of workability for producing the photoalignment film.
Specific examples of the organic solvent include ketones (for example, acetone, 2-butanone, methylisobutylketone, cyclohexanone, cyclopentanone, etc.), ethers (for example, dioxane, tetrahydrofuran, etc.), and aliphatic hydrocarbons. Classes (eg, hexane, etc.), alicyclic hydrocarbons (eg, cyclohexane, etc.), aromatic hydrocarbons (eg, toluene, xylene, trimethylbenzene, etc.), carbon halides (eg, dichloromethane, dichloroethane, di, etc.) Chlorobenzene, chlorotoluene, etc.), esters (eg, methyl acetate, ethyl acetate, butyl acetate, etc.), water, alcohols (eg, ethanol, isopropanol, butanol, cyclohexanol, etc.), cellosolves (eg, methylcellosolve, ethyl, etc.) Examples include cellosolves), cellosolve acetates, sulfoxides (eg, dimethylsulfoxide, etc.), amides (eg, dimethylformamide, dimethylacetamide, etc.), etc., and these may be used alone or in combination of two or more. It may be used together.

The composition for a photoalignment film of the present invention may contain components other than the above, and examples thereof include a cross-linking catalyst, an adhesion improver, a leveling agent, a surfactant, and a plasticizer.

[Manufacturing method of photoalignment film]
The photoalignment film of the present invention can be produced by a conventionally known production method except that the above-mentioned composition for a photoalignment film of the present invention is used. For example, the above-mentioned composition for a photoalignment film of the present invention is supported. It can be produced by a manufacturing method including a coating step of applying to the body surface and a light irradiation step of irradiating the coating film of the composition for a photoalignment film with polarized light or non-polarizing light from an oblique direction on the coating film surface. it can.
The support will be described later in the optical laminate of the present invention.

<Applying process>
The coating method in the coating step is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include spin coating, die coating, gravure coating, flexographic printing, and inkjet printing.

<Light irradiation process>
In the light irradiation step, the polarization to be applied to the coating film of the composition for the photoalignment film is not particularly limited, and examples thereof include linearly polarized light, circularly polarized light, and elliptically polarized light.
Further, the "diagonal direction" of irradiating non-polarized light is not particularly limited as long as it is tilted by a polar angle θ (0 <θ <90 °) with respect to the normal direction of the coating film surface, depending on the purpose. It can be appropriately selected, but it is preferable that θ is 20 to 80 °.

The wavelength in polarized light or non-polarized light is not particularly limited as long as it can impart the ability to control the orientation of liquid crystal molecules to the coating film of the composition for a photoalignment film, and is, for example, ultraviolet rays, near ultraviolet rays, and visible light. And so on. Of these, near-ultraviolet rays of 250 nm to 450 nm are particularly preferable.
Examples of the light source for irradiating polarized or unpolarized lamps include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps. By using an interference filter, a color filter, or the like for ultraviolet rays and visible rays obtained from such a light source, the wavelength range to be irradiated can be limited. Further, linearly polarized light can be obtained by using a polarizing filter or a polarizing prism for the light from these light sources.

The amount of polarized or unpolarized integrated light is not particularly limited as long as the coating film of the composition for a photoalignment film can be imparted with an orientation control ability for liquid crystal molecules, and is not particularly limited, but is 1 to 300 mJ. / Cm ² is preferable, and 5 to 100 mJ / cm ² is more preferable.
The polarized or unpolarized illuminance is not particularly limited as long as it can impart the ability to control the orientation of liquid crystal molecules to the coating film of the composition for a photoalignment film, but is 0.1 to 300 mW / cm ^2. Preferably, 1 to 100 mW / cm ² is more preferable.

[Optical laminate]
The optical laminate of the present invention is an optical laminate having the above-mentioned photoalignment film of the present invention and an optically anisotropic layer formed by using a liquid crystal composition containing a liquid crystal compound.
Further, the optical laminate of the present invention preferably further has a support, and specifically, preferably has a support, a photoalignment film, and an optically anisotropic layer in this order. ..

[Optically anisotropic layer]
The optically anisotropic layer contained in the optical laminate of the present invention is not particularly limited as long as it is an optically anisotropic layer containing a liquid crystal compound, and a conventionally known optically anisotropic layer may be appropriately adopted and used. it can.
Such an optically anisotropic layer is a layer obtained by curing a composition containing a liquid crystal compound having a polymerizable group (hereinafter, also referred to as "composition for forming an optically anisotropic layer"). It may be a single-layer structure or a structure in which a plurality of layers are laminated (laminated body).
The liquid crystal compound and any additive contained in the composition for forming an optically anisotropic layer will be described below.

<Liquid crystal compound>
The liquid crystal compound contained in the composition for forming an optically anisotropic layer is a liquid crystal compound having a polymerizable group.
Generally, liquid crystal compounds can be classified into rod-shaped type and disk-shaped type according to their shape. Furthermore, there are low molecular weight and high molecular weight types, respectively. A polymer generally refers to a polymer having a degree of polymerization of 100 or more (polymer physics / phase transition dynamics, by Masao Doi, p. 2, Iwanami Shoten, 1992).
In the present invention, any liquid crystal compound can be used, but it is preferable to use a rod-shaped liquid crystal compound or a discotic liquid crystal compound, and it is more preferable to use a rod-shaped liquid crystal compound.

In the present invention, a liquid crystal compound having a polymerizable group is used for immobilization of the liquid crystal compound described above, but it is more preferable that the liquid crystal compound has two or more polymerizable groups in one molecule. When the liquid crystal compounds are a mixture of two or more kinds, it is preferable that at least one kind of liquid crystal compounds has two or more polymerizable groups in one molecule. After the liquid crystal compound is fixed by polymerization, it is no longer necessary to exhibit liquid crystal property.

The type of the polymerizable group is not particularly limited, and a functional group capable of an addition polymerization reaction is preferable, and a polymerizable ethylenically unsaturated group or a ring-polymerizable group is preferable. More specifically, a (meth) acryloyl group, a vinyl group, a styryl group, an allyl group and the like are preferably mentioned, and a (meth) acryloyl group is more preferable. The (meth) acryloyl group is a notation that means a meta-acryloyl group or an acryloyl group.

As the rod-shaped liquid crystal compound, for example, those described in claim 1 of JP-A-11-513019 and paragraphs <0026> to <0998> of JP-A-2005-289980 can be preferably used, and disco As the tick liquid crystal compound, for example, those described in paragraphs <0020> to <0067> of JP-A-2007-108732 and paragraphs <0013> to <0108> of JP-A-2010-244038 are preferably used. However, it is not limited to these.

<Additives>
The composition for forming an optically anisotropic layer may contain components other than the liquid crystal compounds described above.
For example, the composition for forming an optically anisotropic layer may contain a polymerization initiator. The polymerization initiator used is selected according to the type of polymerization reaction, and examples thereof include a thermal polymerization initiator and a photopolymerization initiator. For example, examples of photopolymerization initiators include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, and combinations of triarylimidazole dimers and p-aminophenyl ketones. Be done.
The amount of the polymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the total solid content of the composition.

Further, the composition for forming an optically anisotropic layer may contain a polymerizable monomer from the viewpoint of the uniformity of the coating film and the strength of the film.
Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds. It is preferably a polyfunctional radical polymerizable monomer, which is copolymerizable with the above-mentioned polymerizable group-containing liquid crystal compound. For example, those described in paragraphs <0018> to <0020> in JP-A-2002-296423 can be mentioned.
The content of the polymerizable monomer is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, based on the total mass of the liquid crystal compound.

Further, the composition for forming an optically anisotropic layer may contain a surfactant from the viewpoint of the uniformity of the coating film and the strength of the film.
Examples of the surfactant include conventionally known compounds, and a fluorine-based compound is particularly preferable. Specifically, for example, the compounds described in paragraphs <0028> to <0056> in JP 2001-330725, and the compounds described in paragraphs <0069> to <0126> in JP 2005-062673. Can be mentioned.

Further, the composition for forming an optically anisotropic layer may contain an organic solvent. Examples of the organic solvent include those similar to those described in the above-described composition for a photoalignment film of the present invention.

Further, the composition for forming an optically anisotropic layer includes a polarizer interface-side vertical alignment agent, a vertical alignment accelerator such as an air interface-side vertical alignment agent, a polarizer interface-side horizontal alignment agent, and air. Various alignment agents such as a horizontal alignment accelerator such as an interface-side horizontal alignment agent may be contained.
Further, the composition for forming an optically anisotropic layer may contain an adhesion improver, a plasticizer, a polymer and the like in addition to the above components.

The method for forming the optically anisotropic layer using the composition for forming the optically anisotropic layer having such a component is not particularly limited, and for example, the optically anisotropic layer is formed on the above-mentioned photoalignment film of the present invention. It can be formed by applying the forming composition to form a coating film, and then subjecting the obtained coating film to a curing treatment (ultraviolet irradiation (light irradiation treatment) or heat treatment).
The composition for forming an optically anisotropic layer can be applied by a known method (for example, a wire bar coating method, an extrusion coating method, a direct gravure coating method, a reverse gravure coating method, a die coating method).

In the present invention, the thickness of the optically anisotropic layer is not particularly limited, but is preferably 0.1 to 10 μm, and more preferably 0.5 to 5 μm.

[Support]
As described above, the optical laminate of the present invention may have a support as a base material for forming the optically anisotropic layer.
Examples of such a support include a polarizer, a polymer film, and the like, and a combination thereof, for example, a laminate of a polarizer and a polymer film, and a laminate of a polymer film, a polarizer, and a polymer film. It may be a body or the like.
Further, the support may be a temporary support that can be peeled off after forming the optically anisotropic layer (hereinafter, may be simply referred to as “temporary support”). Specifically, a polymer film that functions as a temporary support may be peeled off from the optical laminate to provide an optically anisotropic layer. For example, an optical laminate including an optically anisotropic layer and a temporary support is prepared, and the optically anisotropic layer side of the optical laminate is bonded to a support containing a polarizer with an adhesive or an adhesive. By peeling off the temporary support contained in the optically anisotropic layer, a laminated body of the support containing the polarizer and the optically anisotropic layer may be provided.

<Polarizer>
In the present invention, when the optical laminate of the present invention is used in an image display device, it is preferable to use at least a polarizer as a support.
The polarizer is not particularly limited as long as it is a member having a function of converting light into specific linearly polarized light, and conventionally known absorption-type polarizers and reflection-type polarizers can be used.
As the absorption type polarizer, an iodine-based polarizer, a dye-based polarizer using a dichroic dye, a polyene-based polarizer, and the like are used. Iodine-based polarized light and dye-based polarized light include coated and stretched polarized light, and both can be applied. However, polarized light produced by adsorbing iodine or a dichroic dye on polyvinyl alcohol and stretching it. Children are preferred.
Further, as a method for obtaining a polarizer by stretching and dyeing a laminated film having a polyvinyl alcohol layer formed on a substrate, Japanese Patent No. 5048120, Japanese Patent No. 5143918, Japanese Patent No. 46910205, and Japanese Patent No. Japanese Patent No. 4751481 and Japanese Patent No. 4751486 can be mentioned, and known techniques relating to these polarizers can also be preferably used.
As the reflective polarizer, a polarizer in which thin films having different birefringences are laminated, a wire grid type polarizer, a polarizer in which a cholesteric liquid crystal having a selective reflection region and a 1/4 wave plate are combined, and the like are used.
Among them, from the viewpoint of handleability, a _{polymer containing a polyvinyl alcohol-based resin (-CH 2-} CHOH- as a repeating unit is intended. In particular, at least selected from the group consisting of polyvinyl alcohol and ethylene-vinyl alcohol copolymers. It is preferable that the polarizer contains (preferably one).

In an embodiment in which the optical laminate of the present invention includes a removable support, the polarizing plate can be manufactured, for example, as follows.
The support is peeled off from the above-mentioned optical laminate, and the layer containing the optically anisotropic layer is laminated on the support containing the polarizer. Alternatively, the above-mentioned optical laminate is laminated on a support containing a polarizer, and then the peelable support contained in the optical laminate is peeled off. At the time of laminating, both layers may be adhered with an adhesive or the like. The adhesive is not particularly limited, but is a curable adhesive of an epoxy compound that does not contain an aromatic ring in the molecule as shown in JP-A-2004-245925, 360 to JP-A-2008-174667. An active energy ray-curable adhesive containing a photopolymerization initiator having a molar absorption coefficient of 400 or more at a wavelength of 450 nm and an ultraviolet curable compound as essential components, a (meth) acrylic compound described in JP-A-2008-174667. In 100 parts by mass of the total amount of (a), a (meth) acrylic compound having two or more (meth) acryloyl groups in the molecule, and (b) having a hydroxyl group in the molecule, and having only one polymerizable double bond. Examples thereof include an active energy ray-curable adhesive containing (meth) acrylic compound and (c) phenolethylene oxide-modified acrylate or nonylphenolethylene oxide-modified acrylate.

The thickness of the polarizer is not particularly limited, but is preferably 1 to 60 μm, more preferably 1 to 30 μm, and even more preferably 2 to 20 μm.

<Polymer film>
The polymer film is not particularly limited, and a commonly used polymer film (for example, a polarizer protective film) can be used.
Specific examples of the polymer constituting the polymer film include a cellulose-based polymer; an acrylic polymer having an acrylic acid ester polymer such as polymethylmethacrylate and a lactone ring-containing polymer; a thermoplastic norbornene-based polymer; and a polycarbonate-based polymer. Polymers; polyester polymers such as polyethylene terephthalate and polyethylene naphthalate; styrene polymers such as polystyrene and acrylonitrile / styrene copolymers (AS resin); polyolefin polymers such as polyethylene, polypropylene and ethylene / propylene copolymers; vinyl chloride Polymers; amide polymers such as nylon and aromatic polyamides; imide polymers; sulfone polymers; polyether sulfone polymers; polyether ether ketone polymers; polyphenylene sulfide polymers; vinylidene chloride polymers; vinyl alcohol polymers; Vinyl butyral-based polymers; allylate-based polymers; polyoxymethylene-based polymers; epoxy-based polymers; or polymers in which these polymers are mixed can be mentioned.

Of these, a cellulosic polymer represented by triacetyl cellulose (hereinafter, also referred to as "cellulose acylate") can be preferably used.
Further, from the viewpoint of processability and optical performance, it is also preferable to use an acrylic polymer.
Examples of the acrylic polymer include polymethylmethacrylate and the lactone ring-containing polymer described in paragraphs <0017> to <0107> of JP2009-98605A.

The thickness of the polymer film used for the polarizer protective film or the like is not particularly limited, but is preferably 40 μm or less because the thickness of the optical laminate can be reduced. The lower limit is not particularly limited, but is usually 5 μm or more.

In the embodiment in which the polymer film is used as the support that does not peel off from the optical laminate, the glass transition temperature of the support is preferably 100 ° C. or lower because the composition for the photoalignment film of the present invention is more advantageous. ..
Here, in the present specification, a differential scanning calorimetry device (X-DSC7000 (manufactured by IT Measurement Control Co., Ltd.)) puts 20 mg of a sample of the support into a measuring pan, and puts the sample into a measuring pan, and puts the sample into a measuring pan and puts the speed in nitrogen retention. The temperature was raised from 30 ° C. to 120 ° C. at 10 ° C./min and held for 15 minutes, and then cooled to 30 ° C./min at −20 ° C./min. After that, the temperature is raised again from 30 ° C. to 250 ° C., and the temperature at which the baseline starts to change from the low temperature side is defined as the glass transition temperature Tg.

Further, in the present invention, the thickness of the support is not particularly limited, but is preferably 1 to 100 μm, more preferably 5 to 50 μm, and further preferably 5 to 20 μm. The thickness of the support means the total thickness of the polarizer and the polymer film when they are included.

In the embodiment in which the polymer film is used as the support that can be peeled off from the optical laminate, a cellulosic polymer or a polyester polymer can be preferably used. The thickness of the polymer film is not particularly limited, but is preferably 5 μm to 100 μm, more preferably 20 μm to 90 μm for reasons such as handling during production.

[Image display device]
The image display device of the present invention is an image display device having the optical laminate of the present invention.
The display element used in the image display device of the present invention is not particularly limited, and examples thereof include a liquid crystal cell, an organic electroluminescence (hereinafter abbreviated as “EL”) display panel, and a plasma display panel.
Of these, a liquid crystal cell and an organic EL display panel are preferable, and a liquid crystal cell is more preferable. That is, the image display device of the present invention is preferably a liquid crystal display device using a liquid crystal cell as a display element and an organic EL display device using an organic EL display panel as a display element, and the liquid crystal display device is preferable. More preferred.

[Liquid crystal display device]
The liquid crystal display device which is an example of the image display device of the present invention is a liquid crystal display device having the above-mentioned optical laminate of the present invention and a liquid crystal cell.
In the present invention, among the polarizing plates provided on both sides of the liquid crystal cell, it is preferable to use the optical laminate of the present invention as the polarizing plate on the front side.
The liquid crystal cells constituting the liquid crystal display device will be described in detail below.

<LCD cell>
The liquid crystal cell used in the liquid crystal display device is preferably a VA (Virtual Element) mode, an OCB (Optically Compensated Bend) mode, an IPS (In-Plane-Switching) mode, or a TN (Twisted Nematic) mode. It is not limited to.
In the liquid crystal cell in the TN mode, the rod-shaped liquid crystal molecules (rod-shaped liquid crystal compounds) are substantially horizontally oriented when no voltage is applied, and are further twisted to 60 to 120 °. The TN mode liquid crystal cell is most often used as a color TFT liquid crystal display device, and has been described in many documents.
In the VA mode liquid crystal cell, the rod-shaped liquid crystal molecules are substantially vertically oriented when no voltage is applied. In the VA mode liquid crystal cell, (1) a VA mode liquid crystal cell in a narrow sense in which rod-shaped liquid crystal molecules are oriented substantially vertically when no voltage is applied and substantially horizontally when a voltage is applied (Japanese Patent Laid-Open No. 2-). In addition to (described in Japanese Patent Application Laid-Open No. 176625), (2) a liquid crystal cell (SID97, Digist of technique. Papers (Proceedings) in which the VA mode is multi-domainized (MVA (Multi-dominant Vertical Alginment) mode) for expanding the viewing angle 28 (1997) 845), (3) A mode in which rod-shaped liquid crystal molecules are substantially vertically aligned when no voltage is applied and twisted and multi-domain oriented when a voltage is applied (n-ASM mode (Axially symmetric aligned microcell)). Includes liquid crystal cells (described in the proceedings of the Japan Liquid Crystal Discussion Group 58-59 (1998)) and (4) liquid crystal cells in SURVIVAL (Super Ranged Viewing by Vertical Element) mode (presented at LCD (liquid crystal display) International 98). .. Further, it may be any of PVA (Partnered Vertical Alignment) type, optical alignment type (Optical Alignment), and PSA (Polymer-Sustained Alignment). Details of these modes are described in Japanese Patent Application Laid-Open No. 2006-215326 and Japanese Patent Application Laid-Open No. 2008-538819.
In the liquid crystal cell in the IPS mode, the rod-shaped liquid crystal molecules are oriented substantially parallel to the substrate, and the liquid crystal molecules respond in a plane by applying an electric field parallel to the substrate surface. In the IPS mode, black is displayed when no electric field is applied, and the absorption axes of the pair of upper and lower polarizing plates are orthogonal to each other. Methods for reducing leakage light when displaying black in an oblique direction and improving the viewing angle by using an optical compensation sheet are described in JP-A-10-54982, JP-A-11-202323, and JP-A-9-292522. It is disclosed in JP-A-11-133408, JP-A-11-305217, JP-A-10-307291, and the like.

The present invention will be described in more detail below based on examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be construed as limiting by the examples shown below.

[Synthesis of monomer mA-8]

<Synthesis of Intermediate 1>
In a 500 mL three-necked flask, 10 g of glycidyl methacrylate, 16.30 g of 4-methoxycinnamic acid, 2.64 g of tetraphenylphosphonium chloride, 15.5 mg of butylhydroxytoluene (BHT), and 100 mL of dimethylacetamide (DMAc) are mixed. The mixture was stirred at a temperature of 80 ° C. for 10 hours. After allowing to cool to room temperature (23 ° C.), 200 mL of ethyl acetate and 200 mL of water were added, and the organic phase was washed by separating 200 L of 1N hydrochloric acid, 200 L of saturated aqueous sodium hydrogen carbonate, and 200 L of water in this order. The organic phase was dried over magnesium sulfate and the solvent was distilled off. The concentrate was purified by column chromatography to obtain 12.39 g (yield 50%) of Intermediate 1.
<Synthesis of monomer mA-8>
12 g of Intermediate 1, 7.58 g of triethylamine, 1.37 g of dimethylaminopyridine, and 120 mL of dimethylacetamide were mixed in a 500 mL three-necked flask, and the mixture was cooled to an internal temperature of 5 ° C. To this, 7.37 g of 4-methoxycinnamic acid chloride was added in portions so that the internal temperature was 10 ° C. or lower. Further, the mixture was further stirred at an internal temperature of 40 to 45 ° C. for 3 hours. After cooling the reaction solution to room temperature, 240 mL of ethyl acetate and 240 mL of water were added, and the organic phase was separated and washed in the order of 240 mL of 1N hydrochloric acid, 240 mL of saturated aqueous sodium hydrogen carbonate, and 240 mL of water. The organic phase was dried over magnesium sulfate and the solvent was distilled off. By purifying the concentrate by column chromatography, 16.2 g (yield 90%) of the monomer mA-8 forming the repeating unit A-8 described above was obtained.

[Synthesis of monomer mA-1 etc.]
In the synthesis of the monomer mA-8, the following monomers mA-1, mA-2, mA-5, were used in the same manner as the monomer mA-8, except that the cinnamic acid chloride was changed to the corresponding cinnamic acid chloride derivative. mA-6, mA-10 and mA-27 were synthesized, respectively.
The following monomers mA-1 and the like correspond to the monomers forming the repeating unit A-1 and the like described above, respectively.

[Synthesis of monomer mA-32, etc.]
In the synthesis of the monomer mA-8, 3,4-epoxycyclohexylmethyl methacrylate (Cyclomer M100, manufactured by Daicel) was used instead of glycidyl methacrylate, and cinnamic acid chloride was changed to the corresponding cinnamic acid chloride derivative. Synthesized the following monomers mA-32, mA-33 and mA-34, respectively, in the same manner as in the monomer mA-8.
The following monomers mA-32 and the like correspond to the monomers forming the repeating unit A-32 and the like described above, respectively.

[Synthesis of monomer mA-44]

<Synthesis of Intermediate 2>
25 g of phloroglucinol, 40.12 g of triethylamine, and 250 mL of tetrahydrofuran (THF) were mixed in a 1 L three-necked flask, and the mixture was cooled to an internal temperature of 5 ° C. 77.96 g of 4-methoxycinnamic acid chloride was added thereto in divided portions so that the internal temperature was 10 ° C. or lower. Further, the mixture was further stirred at an internal temperature of 40 to 45 ° C. for 3 hours. After cooling the reaction solution to room temperature, 250 mL of ethyl acetate and 250 mL of water were added, and the organic phase was separated and washed in the order of 240 mL of 1N hydrochloric acid, 240 mL of saturated aqueous sodium hydrogen carbonate, and 240 mL of water. The organic phase was dried over magnesium sulfate and the solvent was distilled off. The concentrate was purified by column chromatography to obtain 55.20 g (yield 62%) of Intermediate 2.
<Monomer mA-44>
20 g of Intermediate 2, 6.80 g of triethylamine, 1.09 g of dimethylaminopyridine (DMAP), 15.0 mg of butylhydroxytoluene (BHT), and 250 mL of dimethylacetamide (DMAc) are mixed in a 1 L three-necked flask. The temperature was cooled to 5 ° C. To this, 7.02 g of methacrylic acid chloride was added in portions so that the internal temperature was 10 ° C. or lower. Further, the mixture was further stirred at an internal temperature of 40 to 45 ° C. for 3 hours. After cooling the reaction solution to room temperature, 300 mL of ethyl acetate and 300 mL of water were added, and the organic phase was separated and washed in the order of 300 mL of 1N hydrochloric acid, 300 mL of saturated aqueous sodium hydrogen carbonate, and 300 mL of water. The organic phase was dried over magnesium sulfate and the solvent was distilled off. By purifying the concentrate by column chromatography, 20.0 g (yield 87%) of the monomer mA-44 forming the repeating unit A-44 described above was obtained.

[Synthesis of monomer mA-50]
In the synthesis of the monomer mA-44, the following monomer mA-50 forming the repeating unit A-50 described above was synthesized in the same manner as the monomer mA-44 except that tetrahydroxybenzene was used instead of phloroglucinol. did.

[Synthesis of monomer mA-71]

<Synthesis of Intermediate 3>
In a 3 L three-necked flask, 120 g of 3-cyclohexene-1-methanol, 0.72 g of methyltrioxorenium, 1.44 g of pyrazole, and 600 mL of dichloromethane were mixed and cooled to an internal temperature of 5 ° C. 134.40 g of 35% hydrogen peroxide solution was added dropwise thereto so that the internal temperature was 10 ° C. or lower. Further, the mixture was stirred at an internal temperature of 5 ° C. or lower for 4 hours. After adding a saturated aqueous sodium thiosulfate solution to the reaction solution so that the internal temperature was 10 ° C. or lower, 500 mL of water was added, and the organic phase was further separated twice with 500 mL of water and washed with 500 mL of a saturated aqueous sodium chloride solution. .. The organic phase was dried over magnesium sulfate and the solvent was distilled off. The concentrate was purified by column chromatography to obtain 76.05 g (yield 55.5%) of Intermediate 3.
<Synthesis of Intermediate 4>
74 g of Intermediate 3, 144.0 g of triethylamine, and 760 mL of dichloromethane were mixed in a 2 L three-necked flask, and the mixture was cooled to an internal temperature of 5 ° C. To this, 64.4 g of acrylic acid chloride was added in portions so that the internal temperature was 10 ° C. or lower, and the mixture was added dropwise over 3 hours. Then, the mixture was stirred at 10 ° C. or lower for 2 hours, 50 mL of water was added so that the internal temperature was 10 ° C. or lower, and the organic phase was separated and washed in the order of saturated aqueous sodium hydrogen carbonate and 300 mL of water. The organic phase was dried over magnesium sulfate and the solvent was distilled off. The concentrate was purified by column chromatography to obtain 85.93 g (yield 82%) of Intermediate 4.
<Synthesis of monomer mA-71>
In the synthesis of the monomer mA-32, the monomer mA-71 forming the repeating unit A-71 described above was obtained in the same manner as the monomer mA-32 described above except that the intermediate 4 was used.

[Synthesis of monomer mA-74]

<Synthesis of 4-hydroxystyrene>
100 g of 4-vinylphenyl acetate and 400 mL of ethyl acetate were mixed in a 1 L three-necked flask, and the mixture was cooled to an internal temperature of 5 ° C. 40.0 g of sodium methoxide was added in portions so that the internal temperature was 10 ° C. or lower, and then the mixture was stirred at room temperature for 3 hours. 400 mL of water was added to the reaction solution, and the organic phase was washed by separating the organic phase in the order of 300 mL of 1N hydrochloric acid, 300 mL of water, and 300 mL of saturated brine. The organic phase was dried over magnesium sulfate, and the solvent was distilled off to obtain 50.0 g (yield 67%) of 4-hydroxystyrene.
<Synthesis of Intermediate 6>
In a 1 L three-necked flask, 20 g of 4-hydroxystyrene, 27.74 g of Intermediate 3, 56.76 g of triphenylphosphine, and 400 mL of tetrahydrofuran were mixed and cooled to an internal temperature of 5 ° C. 37.69 g of diethyl azodicarboxylate was added dropwise to a temperature of 10 ° C. or lower, the temperature was raised to room temperature, and the mixture was stirred for 1 hour. The reaction mixture was concentrated and the concentrate was purified by column chromatography to obtain 25.32 g (yield 66%) of Intermediate 6.
<Synthesis of monomer mA-74>
In the synthesis of the monomer mA-32, the monomer mA-74 forming the repeating unit A-74 described above was obtained in the same manner except that the intermediate 6 was used.

[Monomer MB-1]
Commercially available glycidyl methacrylate (Tokyo Chemicals Reagent) was used as the following monomer mb-1 forming the repeating unit B-1 described above.

[Monomer MB-2]
Cyclomer M100 (manufactured by Daicel Corporation) was used as the following monomer mb-2 forming the repeating unit B-2 described above.

[Monomer mb-3]
OXE-30 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) was used as the following monomer mb-3 forming the repeating unit B-3 described above.

[Monomer mb-4]
As the following monomer mb-4 forming the repeating unit B-4 described above, a synthetic product obtained by a condensation reaction of commercially available 2-hydroxyethyl methacrylate and commercially available methacrylic acid chloride was used.

[Synthesis of monomer mC-1]
The following monomer mC-1 was synthesized by the method described in JP-A-2003-505651.

[Synthesis of monomer mC-2]

<Synthesis of 4-acetoxybenzaldehyde>
18.9 g of 4-hydroxybenzaldehyde, 36.7 g of pyridine, 1.89 g of dimethylaminopyridine, and 500 mL of dichloromethane were mixed in a 1 L three-necked flask, and the mixture was cooled to an internal temperature of 5 ° C. 25.0 g of chloride chloride was added dropwise to a temperature of 10 ° C. or lower, the temperature was raised to room temperature, and the mixture was stirred for 1 hour. After concentrating the reaction solution, 300 mL of ethyl acetate and 300 mL of water were added, and the organic phase was washed by separating the organic phase in the order of 300 mL of saturated aqueous ammonium chloride solution, 300 mL of water, and 300 mL of saturated brine. The organic phase was dried over magnesium sulfate and the solvent was distilled off. The concentrate was purified by column chromatography to obtain 25.6 g (yield 71%) of 4-acetoxybenzaldehyde.
<Synthesis of Intermediate 7>
20.0 g of 4-acetoxybenzaldehyde, 22.4 g of malonic acid, 1.83 g of piperidine, and 250 mL of pyridine were mixed in a 500 mL three-necked flask, the temperature was raised to 85 ° C., and the mixture was heated and stirred for 5 hours. 300 mL of 5N hydrochloric acid was added to the reaction solution, and the precipitate was filtered off to obtain 21.1 g (yield 89%) of Intermediate 7.
<Synthesis of Intermediate 8>
20.0 g of Intermediate 7, 100 mL of dichloromethane, and 1 drop of dimethylformamide were mixed in a 500 mL three-necked flask, and the mixture was cooled to an internal temperature of 5 ° C. Subsequently, 20.0 g of oxalyl chloride was added while keeping the internal temperature below 10 ° C. After completion of the dropping, the water bath was removed, the temperature was raised to room temperature, and the mixture was stirred at room temperature for 3 hours. Then, the solvent was distilled off to obtain 21.78 g (yield 99%) of Intermediate 8.
<Synthesis of monomer mC-2>
10 g of 2-hydroxyethyl methacrylate, 7.58 g of triethylamine, 1.37 g of dimethylaminopyridine, and 120 mL of dimethylacetamide were mixed in a 500 mL three-necked flask and cooled to an internal temperature of 5 ° C. To this, 20.7 g of Intermediate 8 was added in portions so that the internal temperature was 10 ° C. or lower. Further, the mixture was further stirred at an internal temperature of 40 to 45 ° C. for 3 hours. After cooling the reaction solution to room temperature, 240 mL of ethyl acetate and 240 mL of water were added, and the organic phase was separated and washed in the order of 240 mL of 1N hydrochloric acid, 240 mL of saturated aqueous sodium hydrogen carbonate, and 240 mL of water. The organic phase was dried over magnesium sulfate and the solvent was distilled off. The concentrate was purified by column chromatography to obtain 20.2 g (yield 83%) of monomer mC-2.

Here, the above-mentioned monomers mC-1 and mC-2 correspond to the monomers forming the repeating units C-1 and C-2 shown below, respectively.

[Example 1]
A flask equipped with a cooling tube, a thermometer, and a stirrer was charged with 5 parts by mass of 2-butanone as a solvent, and nitrogen was refluxed by heating in a water bath while flowing nitrogen at 5 mL / min in the flask. Here, 6 parts by mass of monomer mA-1, 4 parts by mass of monomer mb-2, 1 part by mass of 2,2'-azobis (isobutyronitrile) as a polymerization initiator, and 5 parts by mass of 2-butanone as a solvent. The mixed solution was added dropwise over 3 hours, and the mixture was further stirred for 3 hours while maintaining the reflux state. After completion of the reaction, the mixture was allowed to cool to room temperature and diluted by adding 30 parts by mass of 2-butanone to obtain a polymer solution of about 20% by mass. The obtained polymer solution was poured into a large excess of methanol to precipitate the polymer, the recovered precipitate was filtered off, washed with a large amount of methanol, and then air-dried at 50 ° C. for 12 hours. A polymer P-1 having a photo-oriented group was obtained.

[Examples 2 to 20 and Comparative Examples 1 to 3]
Example 1 except that each of the above-mentioned monomers was used as the monomer forming the repeating unit shown in Table 1 below and the blending amount of each monomer was changed so as to satisfy “X / (X + Y)” shown in Table 1 below. The polymer was synthesized in the same manner as the polymer P-1 synthesized in 1.

[Preparation of composition for photoalignment film]
To 100 parts by mass of tetrahydrofuran, 1 part by mass of the polymer P-1 synthesized in Example 1 and 0.05 parts by mass of a thermoacid generator represented by the following structural formula were added to form a photoaligning film. The thing was prepared.
In the same manner, for each of the polymers synthesized in Examples 2 to 20 and Comparative Examples 1 to 3, a composition for a photoalignment film was prepared by adding 1 part by mass with respect to 100 parts by mass of tetrahydrofuran.

[Preparation of polarizer]
A polarizer having a film thickness of 8 μm was prepared by adsorbing iodine on a stretched polyvinyl alcohol film according to Example 1 of JP-A-2001-141926.

[Preparation of optical laminate]
The composition for each photoalignment film prepared above was applied to one surface of the prepared polarizer by a spin coating method.
After coating, it was dried on a hot plate at 80 ° C. for 5 minutes to remove the solvent, and a photoisomerization composition layer having a thickness of 0.2 μm was formed.
A photoalignment film was formed by irradiating the obtained photoisomerized composition layer with polarized ultraviolet rays (irradiation amounts shown in Table 2 below, using an ultrahigh pressure mercury lamp).
Next, a nematic liquid crystal compound (ZLI-4792, manufactured by Merck & Co., Inc.) was applied onto the photoalignment film by a spin coating method to form a composition layer.
The formed composition layer was once heated to 90 ° C. on a hot plate and then cooled to 60 ° C. to stabilize the orientation.
After that, the temperature was kept at 60 ° C., ^{and the orientation was fixed by ultraviolet irradiation (500 mJ / cm 2} , using an ultrahigh pressure mercury lamp) under a nitrogen atmosphere (oxygen concentration 100 ppm) to form an optically anisotropic layer with a thickness of 2.0 μm. , An optical laminate was produced.

[Liquid crystal orientation]
The prepared optical laminate was observed using a polarizing microscope in a state of being shifted from the quenching position by 2 degrees. As a result, it was evaluated according to the following criteria. The results are shown in Table 2 below.
AA: The liquid crystal director is evenly aligned and oriented, and the display performance is excellent. A: The liquid crystal director is not disturbed and the surface shape is stable. B: The liquid crystal director is slightly disturbed and the surface shape is stable. C: The liquid crystal director is partially disturbed and the surface shape is stable. D: The liquid crystal director is significantly disturbed and the surface shape is not stable, and the display performance is very poor. The surface shape is intended to be a state in which there are no defects such as unevenness and poor orientation when an optical laminate is placed between two polarizing plates arranged with cross Nicols and observed.
Further, in the present specification, the liquid crystal director is intended as a vector in the direction in which the long axis of the liquid crystal molecule is oriented (orientation main axis).

〔Heat-resistant〕
Before applying the nematic liquid crystal compound, the prepared photoalignment film was allowed to elapse at 40 ° C. and 60% relative humidity for 2 hours, and then an optical laminate was prepared in the same manner as the above-mentioned optical laminate. The orientation was observed and evaluated according to the following criteria. The results are shown in Table 2 below.
A: The liquid crystal director is not disturbed and the surface shape is stable. B: The liquid crystal director is slightly disturbed and the surface shape is stable. C: The liquid crystal director is partially disturbed and the surface shape is stable. Inferior D: The liquid crystal director is significantly disturbed and the surface shape is not stable, and the display performance is very poor.

From the results shown in Tables 1 and 2, even if the polymer has a repeating unit A containing two photo-oriented groups, the photo-aligned film using a polymer having no repeating unit containing a crosslinkable group can be found. It was found that both the orientation and the heat resistance were inferior (Comparative Example 1).
Further, the photo-alignment film using a copolymer having a repeating unit containing a photo-oriented group not corresponding to the above formula (1) and a repeating unit B containing a crosslinkable group has either liquid crystal orientation or heat resistance. Was also found to be inferior (Comparative Example 2).
Similarly, it has a repeating unit containing a photo-oriented group that does not correspond to the above formula (1) and a repeating unit B containing a crosslinkable group, and the content mass of the repeating unit B is increased as compared with Comparative Example 2. Similar to Comparative Example 2, it was found that the photoalignment film using the coalescence was inferior in both liquid crystal orientation and heat resistance ^{when the irradiation amount at the time of forming the photoalignment film was 15 mJ / cm 2, and the irradiation amount was 20 mJ.} It was found that when the amount was increased to / cm ² , the liquid crystal orientation was improved (Comparative Example 3).

On the other hand, a photo-alignment film using a copolymer having a repeating unit A represented by the formula (1) containing a photo-oriented group and a repeating unit B represented by the formula (2) containing a crosslinkable group is available. , Both were found to have good liquid crystal orientation and heat resistance (Examples 1 to 20).
In particular, from the results of Examples 2 to 4, R ⁴ in the formula (1) is the is an electron donating substituent, it was found that the liquid crystalline alignment becomes better.
Further, from the results of Examples 5, 14 and 16, it was found that when A in the above formula (1) is a linking group containing an alicyclic hydrocarbon group, the liquid crystal orientation becomes better. ..
Further, from the results of Examples 9 to 11, when the content mass X of the repeating unit A and the content mass Y of the repeating unit B are in the range of 0.45 to 0.65, the liquid crystal orientation is better. It turned out to be.
Further, from the results of Example 11, a copolymer having a repeating unit A represented by the formula (1) containing a photo-oriented group and a repeating unit B represented by the formula (2) containing a crosslinkable group. It was found that the photo-alignment film using the above can exhibit good liquid crystal orientation even when the irradiation amount at the time of forming the photo-alignment film is 10 mJ / cm ^{2 or less.}

Claims (8)

A photo-oriented copolymer having a repeating unit A represented by the formula (1) containing a photo-oriented group and a repeating unit B represented by the formula (2) containing a crosslinkable group.
A photo-oriented copolymer in which the content mass X of the repeating unit A and the content mass Y of the repeating unit B satisfy the following formula (8).
0.4 ≤ X / (X + Y) ≤ 0.8 ... (8)
Formula (1), R ¹ represents a hydrogen atom or a methyl group, L ¹ is an ester bond, or represents a linking group of a combination of a phenylene group and an ether group, A is represented by the following formula (a1) represents ~ a group represented by any one of ^{(a4), R 2, R} 3, R 4, R 5 and ^{R 6} each independently represent a hydrogen atom or a halogen atom, having 1 to 20 carbon atoms, Linear, branched or cyclic alkyl group, linear alkyl halide group having 1 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, aryl group having 6 to 20 carbon atoms, 6 to 20 carbon atoms. Represents a substituent selected from the group consisting of an aryloxy group, a cyano group, an amino group, and a group represented by the following formula (7). Of R ² , R ³ , R ⁴ , R ⁵ and R ⁶ , two adjacent groups may be bonded to form a ring . n represents 2 or 3. The plurality of R ² , R ³ , R ⁴ , R ⁵ and R ⁶ may be the same or different, respectively.
In the formula (2), R ⁷ represents a hydrogen atom or a methyl group, and L ² is a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms and an arylene group having 6 to 12 carbon atoms. , An ether group, a carbonyl group, and a divalent linking group in which at least two or more groups selected from the group consisting of an imino group are combined, and X is any of the following formulas (3) to (5). Represents a crosslinkable group or an acrylate group.
In the formula (7), * represents a bond position with a benzene ring in the formula (1), and R ⁹ represents a linear or cyclic alkyl group having 1 to 20 carbon atoms.
R ⁸ represents any of a hydrogen atom, a methyl group and an ethyl group. The photooriented copolymer according to claim 1, wherein X in the formula (2) is a crosslinkable group represented by the formula (3) or (4). ^{Of R 2} , R ³ , R ⁴ , R ⁵ and R ^{6 in} the formula (1), at least R ⁴ is a halogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms. A linear alkyl halide group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a cyano group, an amino group, and The photoorientable copolymer according to claim 1 or 2, which represents a substituent selected from the group consisting of the groups represented by the above formula (7). R ⁴ in the formula (1) is an electron donating substituent, the electron-donating substituent, having 1 to 20 carbon atoms, straight-chain, branched or cyclic alkyl group, the carbon number The photooriented copolymer according to any one of claims 1 to 2, which is a linear alkyl halide group having 1 to 20 or an alkoxy group having 1 to 20 carbon atoms. The photooriented copolymer according to any one of claims 1 to 4, wherein the content mass X of the repeating unit A and the content mass Y of the repeating unit B satisfy the following formula (9).
0.45 ≤ X / (X + Y) ≤ 0.65 ... (9) A photo-alignment film formed by using the composition for a photo-alignment film containing the photo-orientation copolymer according to any one of claims 1 to 5. An optical laminate having the photoalignment film according to claim 6 and an optically anisotropic layer formed by using a liquid crystal composition containing a liquid crystal compound. An image display device having the optical laminate according to claim 7.